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Deep Dive: Checkpoint Inhibitors at a Crossroads

Key Takeaway: Checkpoint inhibitors are at a pivotal moment in immuno-oncology, with mixed results from recent trials. While some therapies like relatlimab and ivonescimab show promise, many others, particularly targeting TIGIT, have faced setbacks. The market is projected to grow significantly, but challenges remain in improving response rates and ensuring trial results are applicable to broader populations.

Market Sentiment Analysis

POSITIVE FACTORS

  • Bristol Myers Squibb's approval of relatlimab marks a significant advancement.
  • Ivonescimab shows promise in beating Keytruda in a Phase III trial.
  • The immuno-oncology market is projected to grow significantly by 2033.

CONCERNS & RISKS

  • Response rates for checkpoint inhibitors have plateaued at around 30%.
  • Several checkpoint inhibitors, including TIGIT, have failed in trials.
  • Concerns exist about the generalizability of trial results beyond specific populations.

Full Press Release Details

Eleven years after Merck’sKeytrudatransformed the treatment space for several cancers, immuno-oncology—and checkpoint inhibitors (CPI) especially—are, optimistically speaking, at a crossroads. For those who see the glass as half empty, on the other hand, the space is frustratingly stalled.
“The first wave of immuno-oncology has passed us by,” Jeremy Levin, CEO of Ovid Therapeutics, told BioSpace in March.
As of April 2025, the FDA had approved 14 checkpoint inhibitors, but response rates to this type of immunotherapy have plateaued at around30%, leaving 70% of patients out in the cold. Once highly touted checkpoints, such as TIGIT, have largely failed, while CTLA-4 hasn’t yielded nearly the number of therapies as PD-1/PD-L1.
There is hope, however. Bristol Myers Squibb broke through in March 2022 with the FDA approval of relatlimab (marketed in combination with Opdivo asOpdualag), the first LAG-3-blocking antibody, and today, much of the excitement centers on ivonescimab, a PD-1/VEGF bispecific antibody being developed by Summit Therapeutics. With the overall immuno-oncology market projected to reach some$284 billion by 2033, these companies and more are actively vying for a piece of the pie.
DATA SOURCE:MERCK EARNINGS,BIOPHARMA DIVE
Companies targetingTIGIThave been riding a rollercoaster the past five years. Roche spurred excitement for this novel checkpoint in December 2021 with promisingPhase II resultsfrom its anti-TIGIT tiragolumab in combination with its anti-PD-L1 Tecentriq in metastatic non-small cell lung cancer (NSCLC). It was not to last, however, as last year the combofailedto significantly improve progression-free and overall survival versus Keytruda and chemotherapy in NSCLC in a Phase II/III study. This followed similarly disappointing news from Merck, whose anti-TIGIT antibody vibostolimab, when paired with Keytruda, alsofailedin a Phase II NSCLC trial.
The field was somewhat revived last September when iTeos Therapeutics’ anti-TIGIT belrestotug, in combination with GSK’s anti-PD-1 therapy Jemperli,bestedJemperli monotherapy in terms of confirmed objective response rate by 30% in NSCLC.
Other players in this space include BeiGene, AstraZeneca, Gilead and Arcus Biosciences.
Many industry observers extol the value of combination therapies in immuno-oncology. One such combo generating particular attention is a PD-1/VEGF bispecific antibody being developed by Summit Therapeutics. Last September, Summit set the cancer space ablaze when it announced that ivonescimab beat Keytruda in a Phase III trial in advanced NSCLC. Ivonescimab “is really the new . . . wave of checkpoint inhibitors,” Christiana “Chris” Bardon, co-managing partner of MPM BioImpact,toldBioSpacein March.
Analysts cautioned, however, that the “results may or may not be generalizable beyond the China-focused patient population,” where the trial was conducted. Summit is currently running another Phase III trial in NSCLC in the U.S., with an expected primary completion date of April 2028, according toClinicalTrials.gov.
BioNTech is also a contender in this space, gaining full rights to PD-L1/VEGF-A bispecific antibody BNT327/PM8002 in the November 2024acquisitionof partner Biotheus.
How will AI further the development of novel checkpoint inhibitors?
Editor’s note: This article was originally published as a special edition of ClinicaSpace,BioSpace’s weekly newsletter covering clinical trial results and research news, on April 21. You cansubscribe here.

Frequently Asked Questions

What is the current status of checkpoint inhibitors?

Checkpoint inhibitors are facing challenges, with response rates plateauing around 30%.

What recent advancements have been made in checkpoint inhibitors?

Bristol Myers Squibb's relatlimab and Summit's ivonescimab show promising results.

What challenges do TIGIT-targeting therapies face?

Many TIGIT-targeting therapies have failed in recent clinical trials, raising concerns.

How is the immuno-oncology market projected to grow?

The immuno-oncology market is expected to reach approximately $284 billion by 2033.

What is the significance of ivonescimab in trials?

Ivonescimab has shown potential by outperforming Keytruda in a Phase III trial.

Last updated: May 19, 2025